Immortalization of Different Precursors of Glial Cells with a Targeted and Temperature-Sensitive Oncogene

Abstract

Different types of glial precursor cell lines were obtained after stable transfection of brain cells with the pJC-SVLTtsA vector carrying the tsA58 simian virus 40 large T (SVLT) gene driven by the promoter of a gliotropic strain of JC papovavirus. The immortalized cells were conditional for growth: they expressed the SVLT antigen and proliferated at 34°C, but their growth was either reduced or arrested when they were shifted to 39°C. The differentiation characteristics of four representative lines were more extensively studied. The CR15 and CM8 lines displayed properties of bipotential glial progenitors: they were able to express oligodendrocyte markers at both temperatures, but could differentiate into astrocytes only at 39°C. In contrast, the CR19 and CM3r lines corresponded to more committed oligodendrocyte precursors: they expressed various oligodendroglial markers but they could not synthesize the glial fibrillary acidic protein. More particularly, the CM3r mouse cells displayed a typical oligodendrocyte progenitor morphology and expressed the proteolipid protein mRNA.